"Healthcare professionals are advised to carefully weigh the potential risks and benefits of using [Paxil] in women during pregnancy and to discuss these findings as well as treatment alternatives with their patients," the FDA says in a news release.

Paxil Linked to Twice as Many Birth Defects

GlaxoSmithKline recently conducted a study of major birth defects in infants born to women who took antidepressants (including Paxil) during the first trimester of pregnancy.

In a study of more than 3,500 pregnant women, Paxil was linked to twice as many major birth defects as other antidepressants, according to the FDA.

Birth defects are very rare in the U.S., and it's not certain what role, if any, Paxil played in the birth defects seen in the study, notes GlaxoSmithKline.

Changes have been made to the labeling information on pregnancy precautions that accompanies Paxil, says the FDA.

GlaxoSmithKline is a WebMD sponsor.

Most of the birth defects seen in the study were heart related; the most common heart malformations were ventricular septal defects, which are holes between the heart's two main pumping chambers. These are common birth defects overall as well.

The study was a retrospective epidemiological study. That means it looked at large groups of people in hindsight. There was no data on birth defects in babies born to women who didn't take antidepressants during early pregnancy.

From the Company to Doctors

It is "difficult" to determine whether Paxil caused those birth defects, says GlaxoSmithKline in a letter sent to doctors.

In the letter, the company notes that these findings differ from previous studies looking at birth defects and antidepressants.

Data from the large Swedish Medical Birth Registry hasn't shown evidence of increased risk of major birth defects with antidepressants, including Paxil, notes GlaxoSmithKline.

GlaxoSmithKline spokespeople were not immediately available for comment.